Field of the Invention
The present invention relates to a driving device for linear driving, which uses a plate-shaped elastic body.
Description of the Related Art
Conventionally, a driving device that features a compact and light-weight body, high-speed driving, and silent driving has been employed in a lens barrel of an image capturing apparatus or the like. In particular, concerning a driving device for linear driving, Japanese Patent Application Laid-Open No. 2005-57837 discloses a driving device (ultrasonic motor) to be described below.
The ultrasonic motor disclosed in Japanese Patent Application Laid-Open No. 2005-57837 includes a rectangular vibrating plate on which a piezoelectric element is fixed, a friction member that comes into contact with a contact portion provided on the vibrating plate, and a flexible substrate configured to supply power to the piezoelectric element. The vibrating plate obtains a driving force by a vibration generated by the piezoelectric element and moves relative to the friction member. The flexible substrate is fixed to an electrode on the piezoelectric element and led from the fixing portion in the moving direction and thus disposed so as to be folded while bending halfway. Power is supplied to the moving vibrating plate via the flexible substrate including such a bending portion.
In the composition that moves the vibrating plate relative to the friction member, as in the ultrasonic motor disclosed in Japanese Patent Application Laid-Open No. 2005-57837, a structure that supplies power via the flexible substrate including a bending portion is indispensable. In this structure, the flexible substrate makes a flection deformation along with the movement of the vibrating plate. With this flection deformation, a load is applied, via the flexible substrate, to the piezoelectric element to which the flexible substrate is fixed. This load impedes a vibration necessary for driving, which is generated by the piezoelectric element, and the driving efficiency of the ultrasonic motor lowers.